Replaceable point excavating tooth



June 18, 1940. YOUNlE 2,204,718

|. ZldwEl amw it i June 18, 1940.,

E. YOUNIE 'RzrLAcEABLEf POINT EXCAVATING room Filed July 10, 19:57 3 Sheets-Sheet 2 June 18, 194-0. L. E. YOUNIE REPLACEABLE POINTEXQAVATING room Filed July 10, 1937 5 Sheets-Sheet 3 enema June 18, 1940 PATENT OFFICE RFQPLACEABLE POINT Lewis E. Younie,

Electric Steel reg., a corporation 0 EXCAVATING 'roo'rn Portland, 0reg., assignor to Foundry Company, Portland,

1' Oregon Application July 10, 1937, Serial No. 153,032

13 Claims.

This invention relates to replaceable point excavating teeth as used on the forward cutting edges of power shovels and drag line buckets.

Ordinarily these teeth are made of manganese steel castings, since this metal has great shock and fatigue resisting characteristics. However;

heat treated alloy forgings of chrome nickel steel have better wear resisting properties and are to be preferred when operating in very abrasive soil, such as gravel. A tooth as made according to the present invention is particularly well adapted for use under the latter conditions, since itis provided with a cutting bit that may be readily drop forged in relatively simpledies and which lends itself well to heat treatment. Also, because of its small size, there is very little wastage in this cutting bit and not much metal is required for its fabrication.

It is an object of this invention to provide a detachable excavating tooth having a cutting point or bit which may be drop forged in relatively simple dies. I

A further object is to provide a means for securing the excavating tooth body and point together so that the assembly is strong and rigid.

A further object is to provide an excavating tooth assembly in which the replaceable cutting point is relatively small and may be discarded when worn without much waste of metal.

A further object is to provide an excavating tooth assembly in which the replaceable cutting point is formed in a section that lends itself well to heat treatment.

Other objects and advantages will become apparent from the following description and from. the accompanying drawings in which:

Fig. 1 is a perspective view of a dipper front embodying this invention;

Fig. 2 is an exploded perspective view ofone of the dipper teeth;

Fig. 3 is a rear elevation of the dipper tooth body casting;

Fig. 4 is a bottom elevation of an assembled dipper tooth;

Figs. 5 and 6 are longitudinal sectional views through the tooth taken in the direction of the arrows along the lines 55 and 6-6 of Fig. 1

. respectively;

Figs. 7 and 8 are transverse sectional views taken in the direction of the arrows along the lines 'l-.'I of Fig. 6 and 8-8 of Fig. 5, respectively;

Fig. 9 is a plan view of a modified cutting bit; and 1 I Fig. 10 is a side elevation of the modified cutting bit shown in Fig. 9;

Figs. 11 and 12 are longitudinal sectional views similar to Figs. 5 and 6, excepting/ that Figs. 11 and 12 illustrate a further modified tooth;

Fig. 13.is a plan view of the modified cutting bit shown in Figs. 11 and 12;

Fig. 14 is a side elevation of the cutting bit shown in Fig. 13;

Figs. 15 and 16 are transverse sectional views 10 taken in the direction of the arrows along the lines I5 and I6 of Figs. 11 and 12 respectively.

Referring to the drawings in which like parts are designated" by like numerals throughout the same: 15

A dipper front I0 is provided with a plurality of sockets I2, in this instance four, in which are secured tangs I4 extending from the rearward side of dipper teeth I6. These tangs I4 are secured in position within the sockets I2 by means 0 of tapered keys I8 which are driven intoregistering tapered slots 20 and 22 positioned transversely of the sockets I2 and tangs I4, respectively.

The above connection between the dipper front 5 I0 and the tooth I6 which now is old in the art and forms no part of this invention is given for clearness of understanding only.

The teeth I6 are alike and interchangeable and, therefore, a description of only one will suflice.

The tooth I6 consists of a base casting 24 which is roughly triangular in longitudinal vertical section and has its top forward face formed to provide two backwardly extending grooves 26 and 28 with a tongue 30 between them. The lower surfaces of the two grooves 26 and 28 form a platform 29 that supports a removable cutting bit -32, while the upper portions of the grooves .26 and 28 have inwardly extending flanges 34, 36, 38 and 40, which narrow the grooves at this point and secure the bit 32 against upward movement relative thereto.

The form of bit shown in Figs. 5, 6 and 10 comprises a flat lower surface 42 and an upper sur- 45 face 44 that extends upwardly from the lower surface at the forward cutting edge backwardly at a sharp angle to a plane surface 48 which is parallel with the lower surface 42. This particular form of the bit 32 lends itself to fast operation 50 in earth that may be worked comparatively easily. In addition to this, as the cutting edge 46 recedes under wear, the bit will also wear at the heel of the face 44. This operates to maintain a reasonably sharp bit throughout its life with littie, if any, attention, since the face 44, which recedes under wear, moves into a portion of the bit under face 48, which has a uniform thickness, whereby the cutting angularity between the faces 44 and 42 is maintained substantially constant throughout the life of the bit.

The other form of the bit, 32', illustrated in Figs. 11 to 16, is one that works to advantage under heavy or particularly rough working conditions. This embodiment of the invention has the upper front surface 44' extending at a continuous angle from the lower surface 42 until very close to the heel of the bit 32' after which I it follows a convex curved contour 43 terminating as at 45, where the curved configuration is continued in the body structure of the base casting 24, as at 41. I'his provides a particularly heavy and protective thickness of metal where it is worn away the most by heavy abrasive work and where it will assist the work of the bit 32' to the best advantage, so as to prolong the life of the bit against such wear and work conditions as would have weakened the bit to a breaking point long before its period of usefulness was over.

Extending-rearwardly from the surface 48 in the bit 32, and beginning at the curved contour 43 in the bit 32', the bits are provided with two fingers 50 and 52 or. 50' and 52' respectively which are formed to slide into and be engaged by the walls of the grooves 26 and 28.

The rearward portions of the two fingers are provided with transverse notches 54 and 56 or 54' and 56' respectively in their upper surfaces. When the fingers 50 and 52 or 50 and 52' are slid into the grooves 26 and 28, the notches '54 and 56 or 54 and 56' are aligned with a slot 58 extending transversely through the casting 24.

In this position the bit is rigidly secured to the base 24 by means of a tapered key 60 that is driven into the slot 58 and through the above described notches.

In the assembled position the cutting edge of the bit extends below the bottom edge of the base portion of the tooth and protects the lower surface of the casting 24 against excessive abrasion.

Under some circumstances it may be found that the notches 54 and 5B or 54 and 56' will weaken the fingers to an unsafe point. Under these conditions I prefer to weld metal strips 62 and 64 across the top of the notches as shown in Figs.

9, 10, 13 and 14 thus strengthening the cutting bit at this point and providing a slot 66 66 instead of the open notches for the passage of the key 60,

From the above description it will be seen that I provide a replaceable point dipper tooth that is very strong and rigid and in which the replaceable point or bit is comparatively small and may be forged from very simple dies. This is especially true, since the lower surface of the bit is flat, thereby necessitating the engraving of only the drop forging die from which the upper surface of the bit is formed.

The word bucket" in the claims is used in its broad sense and is generic as to buckets, dippers and shovels used on various types of power excavating machines.

While I haveshown a specific embodiment, it is to be understood that this invention may assume various forms, for instance more or less than two fingers 50 and 52 and grooves 26 and 28 may be used depending upon the size of the tooth, and that the scope of my invention is to be limited only by the following claims.

I claim:

1. A composite excavating tooth, having a base portion for detachable mounting in a bucket socket, upwardly inclined openings in said base portion, a cutting bit having a plane lower surface and a portion of its upper surface inclined thereto, rearwardly extending fingers on said bit to fit said upwardly inclined openings, 9. flat shelf on the base portion projecting ahead of said openings to support the lower surface of said bit, and means to detachably secure said fingers in said openings.

2. A composite tooth of the type described, having a base portion for detachable mounting in a bucket cutting edge, upwardly and rearwardwardly extending slots open at the top in said base portion, a cutting bit having fingers to fit said slots, interlocking means to prevent upward movement of the bit relative to said base portion,

a downwardly and forwardly inclined shelf projecting ahead of said slots and underlying said bit to support said bit against downward flexure, and means to detachably secure the bit against outward movement relative to said base portion.

3. A composite tooth of the type described, having a base portion for detachable mounting in a bucket cutting edge, upwardly inclined openings in said base portion, a cutting bit having a plane lower surface and the front portion of its upper surface inclined thereto, rearwardly extending fingers on said bit to fit said upwardly inclined openings, the lower surface of the fingers being in the same plane as the lower surface of the bit, and means to detachably secure said fingers in said openings with the forward edge of'the bit projecting below the bottom surface of the base portion.

4. A composite excavating tooth, having a base portion for detachable mounting in a bucket socket, rearwardly extending openings in said base portion, a cutting bit having fingers to fit said openings, the lower portion of the base portion projecting forwardly of said openings to provide a flat shelf underlying said bit and means to detachably secure said fingers in said openings.

5. A composite excavating tooth, having a wedge shaped base portion, an upwardly inclined slot open at the top in said base portion, said slot being larger at the bottom than at the top and tapering inwardly toward its inner end, a relatively thin cutting bit having a rearwardly extending tapered finger to fit said slot, the lower portion of said finger being wider than its upper portion, means to support said bit against downward fiexure, said means comprising a downwardly and forwardly inclined shelf on said base portion projecting ahead of said inclined slot, and means to secure the bit rigidly to said base portion.

6. A composite excavating tooth comprising a base portion for detachable mounting in a bucket cutting edge, upwardly inclined openings in said base portion, a cutting bit, rearwardly extending fingers on said bit to. fit said upwardly inclined openings, and means for detachably securing said fingers in said openings said bit having a plane lower surface and its upper surface inclined thereto over its front portion and convex over its rear portion with a slot extending transversely across the top of the convex portion.

'7. A relatively thin excavating tooth having a plane lower surface and the front portion of its upper surface inclined thereto, rearwardly extending fingers on said tooth, the lower portion of said fingers being wider than the upper por- 2,204,718 tion, and the rear portionof said fingers being I provided with transverse notches in their upper surfaces.

8. A composite excavating tooth, having a baseportion with a groove therein, a shelf projecting ahead of said groove said groove being tapered from front to back, a removable cutting bit overlying said shelf and supported thereby and having a tapered tongue to'fit said groove, the lower surface of said tongue being in the same plane as the lower surface of the cutting portion of the bit, and means to removably secure the bit and base portion together.

9. An excavating tooth comprising, a tooth base having an opening in its upper surface, said opening being tapered from front to back, and a portion of said opening being wider than the top thereof, a removable cutting bit having a tongue to fit said opening and limit the inward and upward movement of said bit relative to said tooth base, a flat shelf on said base projecting ahead of said opening and underlying said bit, the contiguous surfaces of the bit and tooth base limiting the downward movement of said bit, and means to removably secure the bit to said tooth base.

10. A composite excavating tooth having a detachable base portion for mounting in a bucket socket, said base portion being provided with openings, a thin flat cutting bit having fingers substantially in the plane of the bit to fit said openings, a shelf on said base portion projecting V ahead of the openings therein to support said bit, and means detachably to secure said fingers in said openings.

11. A, composite tooth of the class described having a detachable base portion for mounting in a bucket cutting edge and provided with slots open at the top, a cutting bit having fingers to fit said slots, interlocking means to prevent up-j ward movement of the bit relative to the base portion, a shelf projecting ahead of said slots and underlying said bit to support the same against downward fiexure, and means detachably to se-i,

cure said bit against movement relative. to said base portion.

12. An excavating tooth bit, comprising a metal member, having a body provided with a relatively sharp edge formed by the juncture of an upper downwardly beveled wearing surface and a lower bearing surface, the said body having a medial portion of substantially uniform thickness adapted to be used up as the beveled wearing surface is worn back, whereby the beveled wearing surface may be maintained of substantially the same characteristics as the tooth is worn back, said bit having a pair of rearwardly extending separated fingers the bases of which are located in substantially the same plane, which plane passes through the sharp edge of said bit, said fingers being provided with an enlarged transverse pin engaging surface.

13. An excavating tooth bit, comprising a metal member having a body provided with a relatively sharp edge formed by the juncture of an upper downwardly beveled wearing surface and a lower bearing surface, the said body having a medial portion of substantially uniform thickness adapted to be used up as the beveled wearing surface is worn back, whereby the beveled wearing surface may be maintained of'substantially the same characteristics as the tooth is worn back, said bit having a pair of rearwardly extending separatedfingers, said fingers being provided with a transverse pin engaging surface, said lower bearing surface and the lower surface of said fingers being in substantially the same plane which passes through the sharp edge of said bit, and said fingers tapering towards their ends and de-* creasing in lateral dimension away from said latter plane.

L W S E. YOUNIE. 

